Incandescent lamp

Abstract

An incandescent lamp is provided which prevents disconnection of a coupling part between a filament and a lead wire and also which improves impact resistance. A lead wire 4 has, in a standing portion 11 inside of a bulb 2, a first zone 19a to a third zone 19c in order from a top. The third zone 19c further penetrates through a pinch seal part 3 while firmly fixed thereto. The first zone 19a and the second zone 19b are formed of materials consisting primarily of molybdenum and nickel, respectively. The third zone 19c is formed of a Dumet wire 29.

Description

BACKGROUND OF THE INVENTION[0001]Field of the Invention[0002]The present invention relates to an incandescent lamp loaded in, for example, an automobile.[0003]Description of the Related Art[0004]An incandescent lamp is known, as an automobile headlight, which includes: a bulb made of soft glass; a sealing part made of soft glass sealing the bulb; a pair of lead wires which has, in the bulb, standing portions standing from the sealing part in a manner such as to face each other and which penetrates through the sealing part while being firmly fixed thereto to be exposed to an outside of the sealing part; a filament which is arranged between the standing portions of the pair of lead wires and which has both end parts held at tip parts of the respective standing portions; and a bridge made of soft glass which is arranged between the standing portions of the pair of lead wires on a side located closer to the sealing part than the filament and which has both end parts coupled to the respe...

AI Technical Summary

Benefits of technology

[0010]It is an object of the present invention to provide an incandescent lamp which achieves further disconnection prevention with reinforced vibration resistance and impact resistance.

[0012]With one aspect of the invention, the first zone and the second zone, which have the higher Young's moduli than the Dumet wire or the nickel plating film-fitted Dumet wire of the third zone, occupy the standing portion. As a result, stiffness of the standing portion increases, thus reinforcing vibration resistance and impact resistance of the incandescent lamp, which permits further prevention of holding part disconnection.

[0014]With the aforementioned configuration, the pair of lead wires holds the filament in the first zone consisting primarily of molybdenum, that is, the first zone is substantially formed of a non-alloy, single material with a high melting point, which makes it possible to suppress embrittlement of a holding part of the lead wire holding the filament and suppress the disconnection.

[0018]With the aforementioned configuration, a surface area of the part of the second zone penetrating through the bridge increases. As a result, after melting and cooling of the bridge upon production, adhesion to the bridge improves, a degree of coupling between the bridge and the second zone increases, thereby improving the vibration resistance and the impact resistance of the incandescent lamp.

Problems solved by technology

Incandescent lamps loaded in, for example, automobiles are subject to vibration and impact.

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